Highly Luminescent AuAg Nanoclusters with Aggregation-Induced Emission for High-Performance White LED Application

Abstract

Highly luminescent metal nanoclusters (MNCs) with aggregation-induced emission (AIE) have emerged as a new class of functional materials, which could be deployed to address challenging issues in diverse fields. In view of the wide application of white light-emitting diodes (WLEDs), which suffer from a low color rendering index (CRI, ≤70) and chromaticity parameter drift, we report the development of a high-performance WLED with high luminous efficiency (LE), excellent CRI attributes, and nonchromaticity parameter drift, achieved by employing AIEfeatured orange-emitting bimetallic AuAg NCs as a red phosphor. The delicately designed AuAg NCs with ultrasmall size (< 2 nm) have strong emission in the orange-light region (∼610 nm) with a large Stokes shift and more importantly show a very stable yet high absolute photoluminescence quantum yield of 43% in the solid state owing to the AIE property, which makes them suitable for constructing WLEDs for high-end lighting applications. The as-developed AuAg NC-based WLED exhibits an excellent CRI (80.6) and high LE (91.9 lm/W) without chromaticity parameter drift. This study is of broad interest because it not only demonstrates the usage of novel luminescent MNCs for WLED applications but also offers a feasible way for the design of high-performance WLEDs with a high LE, high CRI, and nonchromaticity parameter drift.

Driving Forces and Routes for Aggregation-Induced Emission-Based Highly Luminescent Metal Nanocluster Assembly

“…Aggregation-induced emission (AIE) phenomenon is now well-recognized as one of the most promising and emerging fields in a wide range of research domains. , The rapid growth in the number of newly developed AIE active molecules (AIEgens) and the fundamental understanding of the AIE mechanism have greatly enriched their structural diversity. These AIEgens often outperform conventional fluorophores in many research areas because of their unique features such as strong photoluminescence (PL), good solubility, versatility, and high photostability. , For this reason, many of the AIEgens now act as essential components in areas such as optoelectronics, LEDs, sensing, bioimaging, and nanomedicine. − …”

“…(A) 2D-doughnut chart showing the type of ligands and metals used to date for the synthesis of AIE-type MNCs. To make these charts, we have considered only the works which reported new type of MNCs with intrinsic AIE phenomenon. ,,,− (B) Crystal structure of Au 22 ( t BuCC) 18 NCs consisting of Au 13 cuboctahedron kernel and three [Au 3 ( t BuCC) 4 ] trimeric staples. Carbon atoms are shown in gray, and the rest are gold atoms.…”

Silver in the Center Enhances Room‐Temperature Phosphorescence of a Platinum Sub‐nanocluster by 18 Times

“…In comparison to semiconductor quantum dots and organic dyes, metal nanoclusters are safer (do not contain toxic elements), biocompatible and less prone to aggregation caused quenching [11–13] . The use of metal nanoclusters as phosphors in white light‐emitting diodes has been receiving much attention due to the nature of aggregation‐induced emission [14–16] …”

“…[11][12][13] The use of metal nanoclusters as phosphors in white light-emitting diodes has been receiving much attention due to the nature of aggregation-induced emission. [14][15][16] However, in the early investigations, metal nanoclusters had very weak photoluminescence (PL), with quantum yield typically in the order of 0.1 % or less. [17,18] Designing strategies are needed but the most fundamental issue; the origin of PL remains unclear.…”

Supramolecular Design Strategies for Color Tuning of Iridium(III) Complexes Using a Common Framework of Cyclometalating Ligands

“…Development of organic luminescent material with high photoluminescence (PL) efficiency in the solid state is important for light emitting diodes (LEDs) and displays. − However, a major problem associated with most of the organic luminescent materials is the quenching of luminescence in the aggregated solid state. − In particular, different from the aggregation-caused quenching (ACQ), the aggregation-induced emission (AIE) phenomenon broadens the application of luminescent materials in the aggregated solid state. − Typically, AIE phenomena have been studied by using a nonsolvent to induce aggregation in solution phase, in irregular bulk solids, , or in the biological cells or by using the closely packed proximal effect in the solid state , where the state of aggregation remains uncontrolled. The attempt to fabricate highly ordered aggregates of AIE active complexes using the supramolecular approach is indeed limited.…”